Class XXIV. Order I. 253 



are without fruit ; the upper ones much smaller, covered with 

 clots of fructification, which unite, so as to overrun the whole 

 under surface. Rocks and hills. Roxbury. Perennial. 







ASPIDIUM THELYPTERIS. Sm. Meadow Shield fern. 



Frond pinnate, its divisions pinnatifid, subcre- 

 nate, distinct at base, decussating ; dots of fructifi- 

 cation confluent. Sm. 



Common in low, moist grounds, about the edges of meadows 

 and swamps. Stipe glabrous. Divisions of the frond long and 

 slender, the lower pairs frequently decussating, or crossing each 

 other ; a circumstance which Dr. Smith has noticed in his spe- 

 cific character. They are pinnatifid, or deeply cut into oblong, 

 roundish segments, which are slightly crenate at the edge, and 

 revolute when in fruit. The first segments of each division are 

 at a little distance from the stipe, and seem to form a parallel 

 line on each side of it, running through the whole length of the 

 frond, a character well represented in the figure of Plukenet. 

 The fruit commences in small dots, and finally overruns the 

 whole under surface of the frond. Perennial. 



ASPIDIUM MARGIN ALE. Sw. Marginal Shield fern. 



Frond pinnate, its divisions subpinnate, glab- 

 rous, with oblong, entire lobes, sinuate-repaud at 

 the base ; dots marginal. 



Syn. POLTPODIUM MARGINALE. L. 



NEPHRODIUM MARGINALE. Mich. 



A larger fern than either of the preceding. Stipe chaffy. 

 Divisions of the frond nearly pinnate. Subdivisions or seg- 

 ments distinct, oblong, obtuse, crenate, contracted at base, af- 

 terward decurrent, so that their common stalk becomes slight- 

 ly winged, or the division pinnatifid. Dots of fructification dis- 

 tinct, round, close to the margin. Their umbilicated involucre 

 is very obvious. Woods. Roxbury. Perennial. 



